Variable focal length lens comprising micromirrors with two degrees of freedom rotation and one degree of freedom translation

Abstract

A micromirror array lens consists of many micromirrors with two degrees of freedom rotation and one degree of freedom translation and actuating components. As a reflective variable focal length lens, the array of micromirrors makes all lights scattered from one point of an object have the same periodic phase and converge at one point of image plane. As operating methods for the lens, the actuating components control the positions of micromirrors electrostatically and/or electromagnetically. The optical efficiency of the micromirror array lens is increased by locating a mechanical structure upholding micromirrors and the actuating components under micromirrors. Semiconductor microelectronics technologies can remove the loss in effective reflective area due to electrode pads and wires. The lens can correct aberration by controlling each micromirror independently. Independent control of each micromirror is possible by known semiconductor microelectronics technologies. The micromirror array can also form a lens with desired arbitrary shape and/or size.

1. A variable focal length lens comprising a plurality of micromirrors with two degrees of freedom rotation and one degree of freedom translation, wherein the two degrees of freedom rotation and one degree of freedom translation of the micromirrors are controlled to change the focal length of the lens and to satisfy the same phase conditions for the lights, wherein the lens is a diffractive Fresnel lens. 
   
   
     2. The lens of  claim 1 , wherein all of the micromirrors are arranged in a flat plane. 
   
   
     3. The lens of  claim 1 , wherein the micromirrors are arranged to form one or more concentric circles to form the lens. 
   
   
     4. The lens of  claim 3 , wherein the micromirrors on each of the concentric circles are controlled by one or more electrodes corresponding to the concentric circle. 
   
   
     5. The lens of  claim 1 , wherein the micromirrors with same displacements are controlled by the same electrodes. 
   
   
     6. The lens of  claim 1 , wherein the micromirror has a fan shape. 
   
   
     7. The lens of  claim 1 , wherein the micromirror have a hexagonal shape. 
   
   
     8. The lens of  claim 1 , wherein the micromirror has a rectangular shape. 
   
   
     9. The lens of  claim 1 , wherein the micromirror has a square shape. 
   
   
     10. The lens of  claim 1 , wherein the micromirror has a triangle shape. 
   
   
     11. The lens of  claim 1 , wherein the reflective surface of the micromirror is substantially flat. 
   
   
     12. The lens of  claim 1 , wherein a control circuitry is constructed under the micromirrors by using semiconductor microelectronics technologies. 
   
   
     13. The lens of  claim 1 , wherein the micromirrors are actuated by electrostatic force. 
   
   
     14. The lens of  claim 1 , wherein the micromirrors are actuated by electromagnetic force. 
   
   
     15. The lens of  claim 1 , wherein the micromirrors are actuated by electrostatic force and electromagnetic force. 
   
   
     16. The lens of  claim 1 , wherein a mechanical structure upholding the micromirrors and actuating components are located under the micromirrors. 
   
   
     17. The lens of  claim 1 , wherein the micromirrors are controlled independently. 
   
   
     18. The lens of  claim 1 , wherein the reflective surface of the micromirror has a curvature. 
   
   
     19. The lens of  claim 18 , wherein curvatures of the micromirrors are controlled. 
   
   
     20. The lens of  claim 19 , wherein the curvatures of the micromirrors are controlled by electrothermal force. 
   
   
     21. The lens of  claim 19 , wherein the curvatures of the micromirrors are controlled by electrostatic force. 
   
   
     22. The lens of  claim 1 , wherein the surface material of the micromirror is the one with high reflectivity. 
   
   
     23. The lens of  claim 1 , wherein the surface material of the micromirror is metal. 
   
   
     24. The lens of  claim 1 , wherein the surface material of the micromirror is metal compound. 
   
   
     25. The lens of  claim 1 , wherein the surface of the micromirror is made of multi-layered dielectric material. 
   
   
     26. The lens of  claim 1 , wherein the lens is an adaptive optical component, wherein the lens compensates for phase errors of light due to the medium between an object and its image. 
   
   
     27. The lens of  claim 1 , wherein the lens is an adaptive optical component, wherein the lens corrects aberrations. 
   
   
     28. The lens of  claim 1 , wherein the lens is an adaptive optical component, wherein the lens corrects the defects of an imaging system that cause the image to deviate from the rules of paraxial imagery. 
   
   
     29. The lens of  claim 1 , wherein the lens is an adaptive optical component, wherein an object which does not lie on the optical axis can be imaged by the lens without macroscopic mechanical movement. 
   
   
     30. The lens of  claim 1 , wherein the lens is controlled to satisfy the same phase condition for each wavelength of Red, Green, and Blue (RGB), respectively, to get a color image. 
   
   
     31. The lens of  claim 1 , wherein the lens is controlled to satisfy the same phase condition for one wavelength among Red, Green, and Blue (RGB) to get a color image. 
   
   
     32. The lens of  claim 1 , wherein the same phase condition for color imaging is satisfied by using the least common multiple of wavelengths of Red, Green, and Blue lights as an effective wavelength for the phase condition. 
   
   
     33. The lens of  claim 1 , wherein the lens is not controlled to satisfy the same phase condition for any wavelength among Red, Green, and Blue (RGB) to get a color image.